import java.util.Scanner;

public class demo01 {
    //杨辉三角的变形
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()){
            int n = sc.nextInt();
            int m=2*n-1;
            int[][] arr = new int[n][m];
            arr[0][0]=1;
            for (int i = 1; i < n; i++) {
                arr[i][0]=1;
                arr[i][2*i]=1;
                for (int j = 1; j < 2 * i; j++) {
                    if (j == 1) {
                        arr[i][j]=arr[i-1][j]+arr[i-1][j-1];
                    }else {
                        arr[i][j] = arr[i - 1][j] + arr[i - 1][j - 1] + arr[i - 1][j - 2];
                    }
                }
            }
            int i = 0;
            for (; i < m ; i++) {
                if (arr[n-1][i] % 2 == 0) {
                    System.out.println(i+1);
                    break;
                }
            }
            if(i==m) {
                System.out.println(-1);
            }
        }
    }
}
